Lewis structure of NHF2

The information on this page is ✔ fact-checked.

Lewis structure of NHF2
Lewis structure of NHF2

The Lewis structure of NHF2 contains three single bonds, with nitrogen in the center, and hydrogen and two fluorines on either side. There are three lone pairs on each fluorine atom, one lone pair on the nitrogen atom, and the hydrogen atom does not have any lone pair.

Steps

By using the following steps, you can easily draw the Lewis structure of NHF2.

#1 Draw skeleton
#2 Show chemical bond
#3 Mark lone pairs
#4 Calculate formal charge and check stability (if octet is already completed on central atom)

Let’s one by one discuss each step in detail.

#1 Draw skeleton

In this step, first calculate the total number of valence electrons. And then, decide the central atom.

  • Let’s calculate the total number of valence electrons

We know that… nitrogen is a group 15 element, hydrogen is a group 1 element, and fluorine is a group 17 element. Hence, nitrogen has five valence electrons, hydrogen has one valence electron, and fluorine has seven valence electrons.

Now NHF2 has one nitrogen atom, one hydrogen atom, and two fluorine atoms.

So the total number of valence electrons = valence electrons of nitrogen atom + valence electrons of hydrogen atom + (valence electrons of fluorine atom × 2)

Therefore, the total number of valence electrons = 5 + 1 + 14 = 20

  • Now decide the central atom

We can not assume hydrogen as the central atom, because the central atom is bonded with at least two other atoms. And hydrogen has only one electron in its last shell, so it can not make more than one bond.

Therefore, choose the central atom from nitrogen and fluorine.

The atom with the least electronegative value is placed at the center. By looking at the periodic table, we get the electronegativity values for nitrogen and fluorine as follows:

Electronegativity value of nitrogen = 3.04
Electronegativity value of fluorine = 3.98

Obviously, nitrogen is less electronegative than fluorine. Hence, assume that nitrogen is the central atom.

So now, put nitrogen in the center and hydrogen and fluorines on either side. And draw the rough skeleton structure for the Lewis structure of NHF2 something like this:

Skeleton structure for Lewis structure of NHF2

#2 Show chemical bond

Place two electrons between the atoms to show a chemical bond. Since nitrogen is surrounded by hydrogen and two fluorines, use six electrons to show three chemical bonds as follows:

Three chemical bonds shown between atoms

#3 Mark lone pairs

As calculated earlier, we have a total of 20 valence electrons. And in the above structure, we have already used six valence electrons. Hence, fourteen valence electrons are remaining.

Two valence electrons represent one lone pair. So fourteen valence electrons = seven lone pairs.

Note that both (nitrogen and fluorine) are the period 2 elements, so they can not keep more than 8 electrons in their last shell. And hydrogen is a period 1 element, so it can not keep more than 2 electrons in its last shell.

Also, make sure that you start marking these lone pairs on outside atoms first. And then, on the central atom.

The outside atoms are hydrogen and fluorines. But hydrogen can not keep more than 2 electrons in its last shell. Hence, don’t mark the lone pairs on hydrogen.

So each fluorine will get three lone pairs. And the central atom (nitrogen) will get one lone pair.

Now draw the Lewis structure of NHF2 something like this:

Lone pairs marked on Lewis structure of NHF2

In the above structure, you can see that the octet is completed on the central atom (nitrogen), and also on the outside atoms. Therefore, the octet rule is satisfied.

After completing the octet, one last thing we need to do is, calculate the formal charge and check the stability of the above structure.

#4 Calculate formal charge and check stability

The following formula is used to calculate the formal charges on atoms:

Formal charge = valence electrons – nonbonding electrons – ½ bonding electrons

Collect the data from the above structure and then, write it down below as follows:

  • For nitrogen atom

Valence electrons = 5
Nonbonding electrons = 2
Bonding electrons = 6

Formal charge = 5 – 2 – ½ (6) = 0

  • For hydrogen atom

Valence electrons = 1
Nonbonding electrons = 0
Bonding electrons = 2

Formal charge = 1 – 0 – ½ (2) = 0

  • For each fluorine atom

Valence electrons = 7
Nonbonding electrons = 6
Bonding electrons = 2

Formal charge = 7 – 6 – ½ (2) = 0

Mention the formal charges of atoms on the structure. So the Lewis structure of NHF2 looks something like this:

Formal charges are calculated, and got the stable Lewis structure of NHF2

In the above structure, you can see that the formal charges of all atoms are zero. Therefore, this is the stable Lewis structure of NHF2.

And each horizontal line drawn in the above structure represents a pair of bonding valence electrons.

Related

External links

Deep

Rootmemory.com was founded by Deep Rana, who is a mechanical engineer by profession and a blogger by passion. He has a good conceptual knowledge on different educational topics and he provides the same on this website. He loves to learn something new everyday and believes that the best utilization of free time is developing a new skill.

Leave a Comment